Mallard Juveniles to Fly?

Helo there:

We have 10 Mallard Juveniles that are 9 weeks and 4 days old  They came into our backyard when they were 1 day old.  Their mother walked them over to go into the pool.  The mother is still with them.  There is one that is deformed, cannot walk properly and I have not seen her fly.  I am going to call a rehabilitation office and have them take care of her.  . When will they fly? They fly 10 feet and that is all.   We need for them to go. How can we get them to fly. away?     Are they able to fly a few miles? Lake Folsom is 3 miles away. People say do not feed them, but they need food for energy because flying takes a lot of energy.  What to do?

thank you